Shaped charge perforator



May 21, 1957 J. DELACOU'R 2,792,783

SHAPED CHARGE PERFORATOR Filed March 15, 1951 INVENTOR nite SHAPED CHARGE PERFORATOR Jacques Delaconr, Paris, France, assignor, by mesne assignments, to Borg-Warner Corporation, Chicago, 11]., a corporation of Illinois The arrangements that use shaped charges or hollow explosive charges for perforating, cutting and the like operations and particularly the arrangements of this type that are used inside bore holes with a view to perforating the pipes lining the walls of said bore holes include generally a hollow member inside which are carried said charges that are arranged therein inside a space filled with air or a gasiform fluid in order to reduce the action of the explosive waves that are propagated transversely of the charges and consequent harsh blow on the walls of the arrangement.

It has been found in accordance with the invention that the destructive action of said waves could be still more reduced and in fact to a considerable extent, by inserting in the chamber surrounding the charge either along the outer walls of said chamber or round the actual charges, parts adapted to produce a diffraction of the explosion waves.

These parts are constituted by rough porous material such as sponge rubber, felt, glass wool or the like or else by plastic material assuming a rough surface such as polystyrene, polyvinyl, nylon and the like or again preferably a metal trellis-work having comparatively wide meshes of a magnitude of about 1 centimeter, that are similar to the trellis-work made of shaving or steel sponge in current use in trade.

There is illustrated diagrammatically by way of example in accompanying drawings a preferred embodiment of the invention. The single figure of the said drawing is a vertical cross-section of a portion of a pipe-perforating arrangement.

In said figure, 1 designates the actual body of the perforator arrangement inside which is fitted, in the manner disclosed in particular in Marcel Schlumbergers specification Ser. No. 128,950, dated November 23, 1949, an element 2 forming the case of the hollow or shaped charge. Said element or case is fitted on one hand in an opening 3 provided in the wall of the body 1, which opening serves for the introduction of the case 2 into the said body and, on the other hand, it engages a recess 4 pro- 2,792,783 Patented May 21, 1957 vided in the wall of the perforator arrangement at a point diametrically opposed to the recess 3. Inside the case 2 is carried a shaped explosive charge 13 the front of which is covered by the conical lining 5. A plug 6 closes normally the opening 3 in front of the shaped charge and engages the front edge of the latter inside said opening while 7 designates the firing fuse for igniting the said charge. When the latter explodes, the jet of gases passes through the plug 6 and perforates the pipe in the bore hole. At the same time, there are produced transverse waves which are directed against the body 1 and these waves risk damaging the inner surface of the body wall.

Now, according to the present invention, there is provided round the charge case 2, as described hereinabove, a mass of material constituted for instance by a metal sponge or trellice-wrok 8 so as to reduce to a considerable extent the destructive action of said waves.

It is possible, of course, to bring various modifications to the above described arrangement without unduly widening thereby the scope of the invention as defined in accompanying claims.

What I claim is:

1. A shaped charge perforating apparatus for use in a borehole including, in combination, an elongated housing to be lowered repeatedly into a borehole and in cluding pressure resistant walls defining a closed air filled chamber, at least one shaped explosive charge containing unit detachably mounted in the chamber transversely on the walls thereof to direct its explosive jet outwardly toward the wall of the borehole, said unit including a container having a relatively hard frangible shell portion encircling said charge, said charge being adapted to fracture the shell portion and to scatter its fragments forefully against the inner walls of the chamber, a sleeve portion of rough, porous material attached to and surrounding the major portion of the shell of the container over the length of the charge therein to diffract the laterally directed shock waves and thereby shield the inner Walls of the chamber from the lateral effects of the explosion, and means to detonate the explosive charge.

2. Apparatus as set forth in claim 1 in which the sleeve is formed of loosely meshed fibrous material.

3. Apparatus as set forth in claim 1 in which the sleeve is formed of metal sponge material.

References Cited in the file of this patent UNITED STATES PATENTS 2,357,068 Barab Aug. 29, 1944 2,415,814 Davis Feb. 18, 1947 2,494,256 Muskat Ian. 10, 1950 2,499,440 Wood Mar. 7, 1950 2,629,325 Sweetman Feb. 24, 1953 2,630,182 Klotz Mar. 3, 1953 2,649,046 Davis Aug. 18, 1953 

